Java java.awt.font Class TextMeasurer（JDK8）

Constructor Detail

• TextMeasurer

  public TextMeasurer(AttributedCharacterIterator text,
                      FontRenderContext frc)

  Constructs a TextMeasurer from the source text. The source text should be a single entire paragraph.

  Parameters:

  text - the source paragraph. Cannot be null.

  frc - the information about a graphics device which is needed to measure the text correctly. Cannot be null.

Method Detail

• clone

  protected Object clone()

  Description copied from class: Object
  Creates and returns a copy of this object. The precise meaning of "copy" may depend on the class of the object. The general intent is that, for any object x, the expression:

   x.clone() != x

  will be true, and that the expression:

   x.clone().getClass() == x.getClass()

  will be true, but these are not absolute requirements. While it is typically the case that:

   x.clone().equals(x)

  will be true, this is not an absolute requirement.

  By convention, the returned object should be obtained by calling super.clone. If a class and all of its superclasses (except Object) obey this convention, it will be the case that x.clone().getClass() == x.getClass().

  By convention, the object returned by this method should be independent of this object (which is being cloned). To achieve this independence, it may be necessary to modify one or more fields of the object returned by super.clone before returning it. Typically, this means copying any mutable objects that comprise the internal "deep structure" of the object being cloned and replacing the references to these objects with references to the copies. If a class contains only primitive fields or references to immutable objects, then it is usually the case that no fields in the object returned by super.clone need to be modified.

  The method clone for class Object performs a specific cloning operation. First, if the class of this object does not implement the interface Cloneable, then a CloneNotSupportedException is thrown. Note that all arrays are considered to implement the interface Cloneable and that the return type of the clone method of an array type T[] is T[] where T is any reference or primitive type. Otherwise, this method creates a new instance of the class of this object and initializes all its fields with exactly the contents of the corresponding fields of this object, as if by assignment; the contents of the fields are not themselves cloned. Thus, this method performs a "shallow copy" of this object, not a "deep copy" operation.

  The class Object does not itself implement the interface Cloneable, so calling the clone method on an object whose class is Object will result in throwing an exception at run time.

  Overrides:

  clone in class Object

  Returns:

  a clone of this instance.

  See Also:

  Cloneable

• getLineBreakIndex

  public int getLineBreakIndex(int start,
                               float maxAdvance)

  Returns the index of the first character which will not fit on on a line beginning at start and possible measuring up to maxAdvance in graphical width.

  Parameters:

  start - the character index at which to start measuring. start is an absolute index, not relative to the start of the paragraph

  maxAdvance - the graphical width in which the line must fit

  Returns:

  the index after the last character that will fit on a line beginning at start, which is not longer than maxAdvance in graphical width

  Throws:

  IllegalArgumentException - if start is less than the beginning of the paragraph.

• getAdvanceBetween

  public float getAdvanceBetween(int start,
                                 int limit)

  Returns the graphical width of a line beginning at start and including characters up to limit. start and limit are absolute indices, not relative to the start of the paragraph.

  Parameters:

  start - the character index at which to start measuring

  limit - the character index at which to stop measuring

  Returns:

  the graphical width of a line beginning at start and including characters up to limit

  Throws:

  IndexOutOfBoundsException - if limit is less than start

  IllegalArgumentException - if start or limit is not between the beginning of the paragraph and the end of the paragraph.

• getLayout

  public TextLayout getLayout(int start,
                              int limit)

  Returns a TextLayout on the given character range.

  Parameters:

  start - the index of the first character

  limit - the index after the last character. Must be greater than start

  Returns:

  a TextLayout for the characters beginning at start up to (but not including) limit

  Throws:

  IndexOutOfBoundsException - if limit is less than start

  IllegalArgumentException - if start or limit is not between the beginning of the paragraph and the end of the paragraph.

• insertChar

  public void insertChar(AttributedCharacterIterator newParagraph,
                         int insertPos)

  Updates the TextMeasurer after a single character has been inserted into the paragraph currently represented by this TextMeasurer. After this call, this TextMeasurer is equivalent to a new TextMeasurer created from the text; however, it will usually be more efficient to update an existing TextMeasurer than to create a new one from scratch.

  Parameters:

  newParagraph - the text of the paragraph after performing the insertion. Cannot be null.

  insertPos - the position in the text where the character was inserted. Must not be less than the start of newParagraph, and must be less than the end of newParagraph.

  Throws:

  IndexOutOfBoundsException - if insertPos is less than the start of newParagraph or greater than or equal to the end of newParagraph

  NullPointerException - if newParagraph is null

• deleteChar

  public void deleteChar(AttributedCharacterIterator newParagraph,
                         int deletePos)

  Updates the TextMeasurer after a single character has been deleted from the paragraph currently represented by this TextMeasurer. After this call, this TextMeasurer is equivalent to a new TextMeasurer created from the text; however, it will usually be more efficient to update an existing TextMeasurer than to create a new one from scratch.

  Parameters:

  newParagraph - the text of the paragraph after performing the deletion. Cannot be null.

  deletePos - the position in the text where the character was removed. Must not be less than the start of newParagraph, and must not be greater than the end of newParagraph.

  Throws:

  IndexOutOfBoundsException - if deletePos is less than the start of newParagraph or greater than the end of newParagraph

  NullPointerException - if newParagraph is null